Patent Document 1 listed below describes a publicly known rear differential gear which is configured to distribute drive force, inputted from an engine through a propeller shaft, to left and right rear wheels and includes a pair of left and right clutches sharing a clutch outer. In this rear differential gear, a slip ring is fixed to center portions, in the left-right direction, of inner peripheral splines of the clutch outer. Frictional engagement members are disposed at both the left and right of the slip ring. The left clutch is engaged by causing a left clutch piston to press the left frictional engagement members against the slip ring, while the right clutch is engaged by causing a right clutch piston to press the right frictional engagement members against the slip ring.